It is well known in the prior art as shown in U.S. Pat. No. 4,853,116 to use a driving motor with an associated gear box propelling a pair of chains to move a grid structure upwardly and thereby lift solids out a liquid-solid mixture in a waste stream. Saw teeth are formed on combinations of displaceable bars and stationary bars to prevent the displaceable bars from becoming blocked. Such a system, while accomplishing its intended purpose, is cumbersome and unusually complex resulting in a high cost assembly of components. A more efficient and cost effective system is needed.